703 
S3 


UC-NRLF 


a  oas 


George  Davidson 


Paper  Head  ••for*  the  San  Francisco  Chapter, 
AMERICAN  INSTITUTE  OF  ARCHITECTS, 


1    (N  ^  0 


THE  IRON  AGE. 


Paper  Read  Before  the  San   Francisco   Chapter, 
American  Institute  of  Architects. 


V.    ERA  OF  MIND,  OR  AGE  OF  MAN 

x  f 


BY    G.    H.    SANDERS,    F.    A. 


Gentlemen,  Fellows  and  Associates  of  the  San  Francisco 
Chapter  of  the  A.  I.  A.: 

Poom  and  Legend,  Kable  and  Myth  glow  with  the  lustre  of  the 
Golden  Age,  and  every  nation  with  a  history,  written  or  unwrit- 
ten, has  a  background  of  romance  which  owes  its  brightness  to 
the  same  luminous  source. 

The  writings  of  the  poets  and  moralists  of  Greece  and  Rome, 
through  which  the  threads  of  authentic  history  have  come  down 
to  us,  draw  their  inspiration  from  a  far-away  time,  which,  like 
the  lingering  afterglow  of  a  glorious  summer's  day,  tells  of  an  era 
when  the  world  was  young,  and  mankind  lived  in  simplicity  and 
innocence,  and  enjoyed  a  happy  immunity  from  the  incumbrances 
and  inconveniences  of  the,  perhaps,  overwrought  civilization  of 
their  and  our  day. 

Both  Hesiod  and  Ovid  describe  not  only  a  golden,  but  a  silver. 
a  bronze  and  an  iron  age,  the  former  interposing  the  heroic  age 
between  the  bronze  and  the  iron.  The  first  four  are  also 
mentioned  as  forming  constituent  parts  of  the  great  image  of 
Nebuchadnezzar's  vision  as  recorded  in  Daniel — one  of  the 
Prophetical  books  of  the  Hebrew  Scriptures.  The  mythology  of 
the  ancients,  as  well  as  the  clay  records  of  Assyria,  are  replete 
with  allusions,  more  or  less  definite,  to  the  same  wondrous 
epoch,  as  well  as  to  the  increasing  degeneracy  of  the  suc- 
ceeding ages. 

But  authentic  or  fabulous  as  these  may  be,  in  the  Genetic 
record  alone  do  we  find  a  coherent,  if  only  figurative,  account 
of  a  condition  of  things  which  could  rationally  afford  an  adequate 
foundation  for  the  all-pervading  idea  of  the  golden  age.  We 
shall  return  to  the  subject  in  our  concluding  remarks,  and  will 
for  the  present  merely  state  that,  of  the  four  ages  above  recog- 
nized, the  last  has  been  commonly  conceded  to  be  the  peculiar 
heritage  of  men  of  the  present  day. 

THE   AGE   OF   IRON. 

But  it  is  not  the  "Iron  Age,"  of  which  we  wish  now  to  speak 
so  mush  as  the  "  Age  of  Fron,"  a  much  more  definite  and  easily 
apprehended,  if  less  comprehensive  idea,  than  that  indicated  by 
the  formsr  term,  which,  indeed,  may  be  taken  to  include  the 
whole  range  of  the  philosophy,  sciences,  arts  and  morals — nay, 
even  the  religion  of  the  times,  with  all  their  respective  concomi 
tants  and  accessories  which  together  make  up  the  life  of  the  man 
of  the  nineteenth  century. 

But  putting  aside  for  the  present  the  uncertain  traditions,  as 
well  as  the  myths  and  allegories  of  the  days  of  old,  the  scientific 
explorer  of  our  times  has  collected,  classified  and  arranged,  in 
orderly  sequence,  the  evidences  of  at  least  three  ages,  neither 
fabulous  nor  figurative,  which  have  prevailed  in  former  times. 
These  are  known  as  the  stone,  the  bronze,  and  our  own  iron  age, 
from  the  material  which  was  most  generally  employed  during  the 
respective  periods  in  the  ordinary  implements  of  utility  and 
defense,  all  the  stages  of  which  may  be  practically  existing 
amongst  various  barbarous  nations  of  our  own  day  and  generation. 

This  brings  us  face  to  face  with  our  subject  proper,  and  the 
chief  element  of  its  title,  viz.:  Iron. 

This  is  a  substance  of  such  world- wide  utility  that  it  is  apt  to 
appear  impossible  to  dispense  with  it.  This,  however,  is  disap- 
proved by  the  history  of  past  times  as  well  as  by  the  known  con- 
dition of  many  peoples  and  tribes  of  the  present  day,  though  their 
position  and  status,  indeed,  may  be  said  to  be  measured  by  the 
degree  of  their  knowledge  and  appreciation  of  this  significant 
material. 

To  fully  comprehend  the  true  position  of  iron  in  the  scale  of 
life,  we  must  glance  at  its  position  in  the  scale  of  creation. 
Accepting  as  such  the  accompanying  Geological  section  of  the 
shell  or  crust  of  the  earth,  we  will  ask  your  attention  to  a  brief 
examination  of  its  component  parts  and  the  manner  of  their 
formation — the  accompanying  section  (1)  (from  Geological  Section 
in  Webster's  Dictionary),  which  is  generally  taken  to  represent  a 
total  thickness  of  about  thirty  miles,  is  just  about  the  330th 
part  of  the  diameter  of  the  earth,  or  about  the  comparative 
thickness  of  an  ordinary  egg  shell. 

The  entire  internal  body  of  the  earth  has  been  supposed  to  be  a 
molten  mass,  and  to  properly  understand  this  wo  must  begin  at 
the  beginning,  and  the  beginning,  in  this  case,  is 

"  NEBULJE." 

In  NTo.  2  we  have  a  representation  of  the  great  nebula  in  Orion. 
The  latter  is  one  of  the  most  conspicuous  constellations  visible  in 
the  southern  heavens  during  the  latter  half  of  the  year,  and  the 


(No.    I). 


Post-tertiary,  Pleistocene,  or  Quaternary. 


Upper  chalks,  with  flinta. 


Lower  chalk. 


}(  Portland  stone  and  Purbeck. 
Oolite  \  Oxford  group. 
(Stonesfield  elate. 


(  Keuper. 

/•  Trias.  J  Muschelkalk. 
(  Bunter 


Connecticut 

Rivur  sand- 

stone, with 

I  foot-prints. 


sandstein. 


Pprmiaii  (  Magnesian  limestone,  orzechstein. 
', "' "i  Red  sandstone  and  marls,  or  Roth- 
!      liegende. 


Coal  measures. 


Millstone  grit 

I  Sub-carboniferous  or 
Mountain  limestone. 


*i 

*••> 

3  -; 

<  = 
r?. 

<  ^ 

5  = 


6.  oaiakiil        XvKvfKv/3  Catokill  red  sand- 
Perio.l.v.WA-.VAvS    stone. 

4.  Chemun7J  p-hemung  group. 

™  Portage  group. 
Genesee  slate. 
Hamilton  group. 

Marcellus  shale. 
Upper  Helderberg 
limestone. 

Schoharie  grit 
Cauda-galli  grit 
Oriskany  sandstone. 
Lower  Helderberg 
group. 

I  Saliferous  beds. 
Niagara  group. 
Clinton  group. 


Old  red  sandstone. 


I  Ludlow  group. 

/  Aymestry  limestone 


L  NiM"  ~i,  >^%g?  Medi"a  sa"dst° 

"•'•''•MS  Orei( 


Wenlock  group 
Upper  Llandovery. 

)  Upper  Caradoc. 

ida  conglomerate.  )  Lower  Llandovery. 
Hudson  River  group. 
I'tica  Shale. 


[•  Lower  Caradoc. 


Trenton.  Black  River  \ 
and    Birdseye  lime-  '  Bala  limestone 


i>erio>1-  |jv:gi  Po 


stones. 
Chazy  limestone. 

|i?^  Calciferous  sandrock. 


f  Llandeilo  flags. 


'tsdam  sandstone      I 


V  Primordial  zone. 


I.     AZOIC  TIME  OR  AGE. 


nebula  is  distinguishable  by  the  naked  eye,  and  constitutes  the 
sword-hilt  of  the  figure.  The  nebula  itself  is  one  of  the  most  ex- 
traordinary objects  to  be  seen  in  the  heavens,  and  is,  in  fact,  one 
of  the  "  show  "  objects  of  the  astronomers.  It  is  notable  on  ac- 
count of  its  vast  extent  as  compared  with  most  of  the  other  neb- 
ulae, as  well  as  its  wonderful  complexity  and  apparent  confusion  of 
parts.  It  was  one  of  the  first  objects  examined  by  Lord  Bosse  in 
his  great  six-foot  reflector,  and  great  was  his  joy  and  astonishment 
to  find  the  vast  cloudy  masses  resolve  themselves  into  myriads  of 
stars !  Some  others  of  the  nebulae  are  not  as  yet  resolvable  when 
seen  through  the  telescope.  The  spectroscope,  however,  is  the 
instrument  especially  relied  on  in  investigations  of  this  kind. 
This  curious  instrument  has  the  power  of  distinguishing  the 
chemical  properties  of  substances  by  the  light  emitted  by  them 
in  an  incandescent  or  highly-heated  condition.  In  this  way  the 
light  of  various  mineral  salts,  gases  and  other  terrestrial  sub- 
stances have  been  compared  with  the  sun,  the  fixed  stars,  and 
even  the  nebulcel  Thus  the  "  spectrum,"  as  it  is  called,  from 
its  shadowy  character,  becomes  a  sort  of  scale  or  gauge  for  the 
qualitative  analysis  of  all  the  rest  of  the  universe;  and  it  is  every- 
where found  to  be  similar,  if  not  altogether  uniform,  in  properties. 


The  spectrum  is  a  luminous  band 
of  prisrnatically-colored  light.  When 
this  is  caused  by  a  beam  of  sunlight, 
the  band  or  spectrum  is  seen  to  be 
crossed  by  a  multitude  of  bright, 
colored  and  dark  lines  and  bands. 
When  the  light  emitted  by  a  va- 
riety of  metallic  substances,  gases, 
etc.,  is  examined,  the  lines  they  pro- 
duce are  found  to  agree  with  some 
of  those  found  in  the  spectrum  of 
the  sun.  The  same  is  found  when 
the  light  of  the  fixed  stars  is  ex- 
amined, as  well  as  the  nebula;,  and 
terrestrial  substances  are  found  in 
all  of  them!  The  nebula;  are  also 
found  to  differ  amon^  themselves, 
just  as  the  stars  do,  but  in  a  differ- 
ent way.  Thus,  some  are  found  to 
exhibit  only  the  lines  caused  by  the 
two  great  gases,  nitrogen  and  hy- 
drogen ;  and  these  have  been  hith- 
erto found  unresolvable  into  stars  by 
the  telescope.  Others  show  bands 
only,  and  these  are  resolvable.  <  >th- 
ers,  again,  show  both  bands  and 
lines,  and  therefore  appear  fo  be  of 
a  mixed  or  compound  order,  and  in 
which  the  original  gaseous  elements, 
which  appear  to  constitute  the  orig- 
inal mass  of  all  nebula,  would  seem 
to  be  in  process  of  conversion  or 
/(•solution  in  the  other  cases  com- 
pleted or  not  yet  commenced. 

The  latest  accepted  theory  in  re- 
gard to  these  mysterious  accumulations  of  serial  substances 
appears  to  be  that,  as  these  vast  masses  of  "drift"  are  caught 
here  and  there  in  the  eddies  arising  from  the  inevitable  friction 
resulting  from  ethereal  motion,  aggregations  of  condensation 
naturally  oc':ur,  and  in  the  vast  sweep  of  inconceivable  ages, 
under  tlie  influence  of  all-pervading  Law,  universes  of  har- 
moniously balanced  solar,  planetary  and  lunar  systems,  with  all 
their  necessary  and  appropriate  accompaniments,  come  into 
being.  The  diagonal  of  centrifugal  and  centripetal  forces  which 
have  arisen  in  the  case  of  each  initial  eddy,  establishes  a  center  of 
gravitational  energy,  which  becomes  in  time  a  sun,  and  the  sun, 
in  the  progressive  evolution  of  being,  becomes  in  turn  an  earth, 
and  by  successive  condensations  and  depositions  of  the  fiery 
gases  in  the  form  of  mo.'e  and  more  solid  materials,  an  orb,  capa- 
ble of  receiving  and  sustaining  life,  slowly  emerges  from  the 
womb  of  creation,  and  a  world  of  life  is  born.  N  The  first  rain- 
drop which  reaches  the  cooled  surface  of  a  new-born  world 
marks  an  epoch.  The  last  that  ever  falls  on  the  same  earth 
marks  another.  Between  them  lies  the  history  of  the  life  of  that 
world  !  * 

The  condensation  and  deposition  of  material  at  first  ethereal, 
then  gaseous,  then  aqueous,  necessarily  include  phenomena 
impossible  to  describe  because  incapable  of  being  seen  by  any 
other  faculty  than  that  of  imagination.  It  can  only  be  said  that 
what  does  occur  must  have  taken  place  in  the  case  of  our  earth 
in  the  order  here  represented.  (No.  1). 

First :  The  igneous  or  primary  rocks  of  the  Azoic  Age  with 
only  the  outer  rim  of  which  we  can  ever  become  acquainted  ; 
then  depositions  of  material  caused  by  erosion  in  the  earliest 
seas  form  vast  strata  which  underlie  all  others  and  have  solidified 


GREAT   NEBULA  IN  ORION.     (No.  2.) 

into  the  rocks  of  the  second  or  Palezoic  series,  succeeded  by  the 
Mesozoic  and  Cenozoic  times  or  ages,  and  finally  by  the  present 
time  or  age,  known  as  the  age  of  mind,  or  of  man. 

The  second  or  Palezoic  series  of  times  or  ages  are  divided  into 
three  great  epochs,  viz.:    The  Silurian  age,  or  age  of  Mollusks;  the 
Devonian   age,  or  age  of  fishes,  and  the  carboniferous  age,    or 
age  of   plants ;  while  the  Mesozic  corresponds  to  the  single  age 
of  reptiles,  and  the  Cenozoic  to  the  Mammalian  age.     All  these 
enormous  periods  are  divided  and  subdivided  again  and  again,  so 
that  every  strata  has  its  place  in  the  vast  whole   in  such  a  way 
as  to  be    readily  recognizable,   if  not   by  its  intrinsic   character- 
istics, it  may   still  be  identified  by  those  of  its  neighbors  above 
and  below.     But  of  the  whole,  it   is  with  the  upper  third  of  the 
second   or  Palezoic  time,   called  the  Carboniferous  age,  that  we 
have  to  do.     The  included  strata  are  known  as  the  coal  measures, 
and  contains    as    well  most    of  the  workable   beds   of  iron  ore. 
Associated  with  the  coal  measures  also  are  vast  strata  of  lime- 
stones, including  the  sub-carboniferous   or  mountain  limestones, 
and    superimposed   beds   of   magnesian   limestones — the   former 
indispensable    as    fluxes,    and    the    latter,  recently  found   to    be 
equally  valuable  as  a  means  of  purifying  the  ore    from  the  phos- 
phorous and  sulphur  often  contained  in  the  coal  used  in  the  pro- 
cess of  converting  the  iron  into  steel.     The  iron  ores,  also,  which 
are  principally  worked,  have  themselves    been  largely  the  result 
of  plant  growth,  as  by  the  process  of  absorption  of  metallic  vapors 
from  the  atmosphere  by  the  vegetation,  and  the  setting  free  of  the 
mineral  thus  held  in  combination  by  the  decay  of  root  fibres,  etc , 
the  oxidized  metal  has  been  carried  down  and  caught   in  the  sub- 
jacent sandstones  and  clay-stone  rocks,  and  so   has  formed  the 
ferrugenous  earths  and  beds  known  as  Iron  stone,  Haemetite,  etc. 
We  thus  see  in  the  very  center  of  the  scale,  asso- 
;iated  with  tho  great   belt  of  the  coal    measures, 
evidences  of  a  time  or  age  of  extraordinary  plant 
growth    and  of  conditions    of  solar,  aqueous    and 
atmospherical    phenomena  unprecedented    in    the 
life  of  our  planet ;  a  time  or  age  of  light  and  heat 
storage,  and  of  strength  and  energy  storage,  and 
of  such  other  peculiar  and  suggestive  combinations 
as  to  justify  to    some  extent  the  claims    of  these 
same  code  measures  as  the  real  bona  fide  iron  age 
after  all ;  or  at  least  it  would  appear  that  by  the, 
shall  we   not  say,    Providential  provisions   of  the 
law  of  natural  selection,  all  the  necessary  elements 
have  been  brought  together  for  the  development  of 
this  present  existing  wonderful  age  or  time,  which 
aH  are  ready  to  recognize  as  the  ''Age  of  Iron." 

The  qualities  of  cast  and  wrought  iron  and 
steel  are  so  well  known  as  scarcely  to  need  men- 
tion, except  for  the  sake  of  reference  hereafter. 


TYPES  OF  STELLAR  SPECERA.  (No.  3). 


Fusibility,  density  and  inflexibility  in  the  case  of  cast 
iron,  and  malleability,  ductility  and  elasticity  in  the  caso 
of  wrought  iron  or  steel  generally  cover  their  respective 
characteristics  and  constitute  their  valuable  properties.  Trans- 
verse strength  and  resistance  to  crushing  in  the  case  of  cast  iron, 
and  of  shearing  in  the  case  of  wrought  iron  as  well  as  the-  still 
more  valuable  capacity  to  resist  tensile  strains  in  the  case  of  the 
latter  substance,  are  in  every  way  enhanced  in  cast  and  wrought 
steel,  and  still  other  valuable  properties  in  wliat  is  known  as 
malleable  cast  iron.  The  Bessemer  and  other  processes  of  con- 
verting pig  iron  into  steel,  or,  still  better,  directly  from  the  ore, 
bv  forcing  a  blast  of  atmospheric  air  through  the  molten  mass  of 
metal  in  a  crucible,  lias  added  so  enormously  to  the  availability 
of  steel  as  a  lighter,  stronger,  and  more  reliable  substitute  for 
ordinary  iron,  for  almost  all  purposes  for  which  the  latter  lias 
hitherto  been  used,  as  almost  to  constitute  as  great  a  possible 
development  in  manufactures  and  means  of  ulti mating  great 
enterprises,  as  the  invention  of  the  steam  engine  itself. 

T1IK    APPLICATION    OF    IRON. 

But  passing  from  this  phase  of  the  subject  to  the  application 
of  iron  in  the  arts  of  construction,  we  will  note  its  progress  as  an 
agent  in  the  accomplishment  of  some  of  the  great  enterprises  of 
the  century. 


When  James  Watts  was  chicled  by  his  parents  for  wasting  his 
time  watching  the  action  of  steam  on  the  tea  kettle  lid,  they 
little  knew  the  tremendous  revolution  in  the  condition  of  the  world 
that  the  boy  was  destined  to  bring  about — neither  more  nor  less 
than  the  virtual  inception  of  the  age  of  iron,  and  thereby  the 
amelioration  of  the  condition,  and,  shall  we  not  say  final  civilization 
of  the  habitable  world,  in  a  way  unattainable  by  any  other  means. 
The  invention  of  the  steam  engine  has  led  to  the  extension  of 
manufactures;  the  conquest  of  the  ocean  by  the  construction  of 
vessels  of  steel,  rivalling  in  dimensions  the  famous  Ark  of  old;  the 
extension  of  the  land  by  the  drainage  of  vast  areas  of  bog,  marsh, 
fen.  and  lake;  the  cutting  of  canals,  and  the  connection  of  oceans 
by  water-ways  like  great  rivers;  the  covering  of  continents  with 
net  works  of  steel  rails;  the  prospective  belting  of  the  world  by 
i. leans  of  telegraphic  cables;  the  conversion  of  our  streets  into 
checkerboards  of  cable  cars,  our  business  houses  into  "cloud 
capped  towers"  indestructable  by  fire:  a-id  the  spanning  of  great 
rivers  and  arms  of  the  sea  by  enormous  structures  in  the  form  of 
bridges,  before  which  the  mightiest  works  of  the  ancients  fade 
into  dolls'  houses,  and  the  very  loftiest  of  which  we  have  any 
positive  knowledge,  are  dwarfed  into  pigmies  in  the  presence  of 
the  Eiffel  tower. 


BRIIX ;  Ks. 


LONDON  OLD  BRIDGE.     (No.  4.) 


The  first  illustrations  to  which  we  will  ask  your  attention  are  a 
number  of  bridgt s.  These  useful  structures  have,  in  all  ages, 
taxed  the  ingenuity  of  engineers  to  construct,  and  may  be  said  to 
have  bi-eii  a  mist  important  means  of  education,  in  enabling  him 
to  surmount  difficulties  and  achieve  success  in  almost  every  direc- 
tion in  which  his  energies  have  been  exerted.  The  first 
structure  we  have  here  represented  is  Old  London  Bridge. 
This  is  a  striking  example  of  the  cumbrous  obstructiveness 
not  unusual  in  the  methods  of  the  past.  It  was  begun  in  1  178, 


by  Peter  of  Cole  Church,  and  was  thirty-three  years  in  building 
Often  covered  with  large  and  picturesque  masses  of  wooden 
buildings  which  were  as  often  destroyed  by" fire — the  main  struc- 
ture appears  to  have  remained  until  the  beginning  of  this  century, 
essentially  as  it  was  built.  The  next  illustration,  which  is 
New  London  Bridge,  was  designed  by  Mr.  George  Rennie,  and 
built  by  his  brother,  Sir  John.  This  a  beautiful  structure;  having 
spans  of  152  feet,  and  twenty-nine  foot  rise  of  arch,  replaced 
the  old  bridge  which  was  removed  to  make  way  for  it. 


LONDON  NEW  BRIDGE. 


(No.  5.) 

Waterloo  Bridge  was  erected  in  1817,  and  is  of  a  similar  char- 
acter to  the  preceding,  being  constructed  of  stone  in  many  arches, 
of  less  span,  but  in  a  wider  part  of  the  river.  See  next  illustra- 
tion. 

But   the  next    example    is    altogether  different  in  material,  if      material  used,  as  it  is  unnecessarily  heavy  and  expensive, 
not  in  form.     Until  recent  years,  stone,   brick  or  timber  was  the 


material  almost  always  employed  in  the  construction  of  bridges; 
but  late  in  the  last  century  cast  iron  began  to  be  employed,  and 
the  specimen  here  shown — Southwark  Bridge  over  the  Thames, 
240  foot  in  span  of  arch,  is  not  regarded  as  a  success,  in  view  of  the 


WATERLOO  BRIIX 


(No.  6.) 


The  next  specimen  here  shown,  the  Menai  Suspension 
Bridge,  (No.  S.)  indicates  a  great  advance  in  the  right  direction. 
The  use  of  chains  or  links  and  wire  cables  on  the  suspension 
principle  began  to  be  quite  usual  before  this  structure  was  com- 
menced by  Telford  in  1819.  It  is  570  feet  span,  and  has  a  versed 
sine  of  forty-three  feet  for  the  curve  of  the  Catenary. 


This  form  of  bridge,  however,  was  not  at  this  time  found  suit- 
able for  railways.  The  objection  raised  on  account  of  vibra- 
tion has  been  obviated  by  the  principle  introduced  in  the 
next  example,  known  as  the  Britannia  Tubular  Bridge,  (No.  9) 
designed  and  built  by  Robert  Stephenson  in  1845.  It  shows  a 


SOUTHWARK  BRIDGE.     (No.  7.) 


complete  revolution  in  the  construction  of  bridges,  which  has 
led  to  vast  results.  This  bridge  consists  of  two  independent 
wrought  iron  tubular  beams  1511  feet  long,  each  15  feet  wide 
and  23  feet  high  at  ends,  and  30  feet  in  center.  The  central 
pier  is  230  feet  high,  and  the  two  center  spans  are  460  feet  each. 
The  land  spans  on  each  side  are  230  feet  each  in  length.  The 
top  and  bottom  flanges  of  these  immense  girder  tubes  are  cellular 


in  construction,  and  the  floor  and  ceiling  are  strengthened  by 
keelsons  and  gi'ssets,  and  the  side  plates  are  strengthened  by  T  irons 
inside  and  out.  See  sec.  (No.  1 1 )  This  bridge,  however,  in  this 
peculiar  form  has  only  once  been  repeated  in  the  Victoria  Bridge 
over  the  River  St.  Lawrence,  in  Canada  which  is  7,000  feet  in 
length,  and  whose  spans  are  almost  equal  to  those  of  the  Britannia 
Bridge.  The  mode  of  construction,  the  methods  of  floating  the 


tubes  into  position  and  raising  them  into  their  places  by  hydraulic 
pressure,  and  the  final  triumphant  success  of  both  these  undertak- 
ings, together  with  the  interesting  incidents  and  imminent  risks 
to  which  both  were  subject,  owing  to  the  dangerous  condi- 


tions attending  their  construction,  has  almost  the  interest  cf 
a  romance,  and  IIRS  raised  both  these  enterprises,  together  with  the 
name  of  their  designer,  into  a  prominence  which  can  never  be 
lost.  Nevertheless,  it  is  certain  that  they  are  never  likely  to  be 


MENAI   SUSPENSION   BRIDGE.      (No.  8) 


repeated,  since  more  economical  and  advantageous 
forms  of  construction  have  arisen  from  the  principle 
which  they  inaugurated,  one  type  of  which  is  the  high 
level  bridge  at  Newcastle.  (No.  12)  This  is  a  combi- 
nation known  as  the  bow  string  girder,  an  open  tube 
carried  on  a  cast  iron  arch  and  wrought  iron  tie  (see 
plan  and  elevation)  presenting  an  appearance  of  great 
lightness  and  beauty  both  being  more  economical,  and 
avoiding  the  disadvantages  of  the  close  tunnel  form 
so  objectionable  in  such  long  structures  as  the  Bri- 
tannia and  Victoria  Bridges,  which  shut  out  light  and 
air,  and  the  fine  scenery  which'such  situations  usually 
present;  but  even  this  form  of  the  tubular  bridge  is 
unnecessarily  expensive,  and  the  experiment  is  not 
likely  to  be  again  made.  It  was  simply  a  combina- 
tion of  the  truss  with  the  arch  and  tube,  both  of 
which  latter  are  wholly  dispensed  with  in  the  next 


IS 


>§ 

o   *» 

6  a 

s* 


BRITANIA  TUBULAR  BRIDGE.     (No.  9) 


example,  shown  in  elevation  and  section,  which  is  the  Newark 
Dyke  Bridge,  Oubitt  Engineer,  erected  in  1853.  (No.  13)  It  is 
the  first,  and  a  fine  specimen  of  the  Warren  girder;  and  on  account 


of  its  economy  of  construction  and  freedom  from  any  unnecessary 
accessories,  is  a  very  frequent  mode  of  truss  construction,  espec- 
ially in  America,  in  wood  and  iron,  or  both. 


The  next  example  is  the  Cruralin  Viaduct,  (No.  14)  which  shows 
another  fine  truss  on  the  same  principle.  It  consists  of  7  spans  of 
100  to  150  feet,  and  is  carried  on  piers  formed  of  hollow  cast  iron 
columns,  12  inches  in  diameter,  braced  together  in  sections  of  17 


HIGH  LEVEL   BRIDGE  AT  NEWCASTLE, 
feet 


Top  Plate  represents  the  Elevation  of  one  Span  of  Bowsting  Arch  of  High  Level  Bridge 
New  Castle.     Lower  Plate  is  the  plan  of  the  same.     (No.  n) 


(No.  12) 

each  in  length.  The  trusses  are  of  wrought  iron,  and 
are  14  feet  G  inches  in  depth.  The  roadway  is  carried  on  the  upper 
string  of  this  example,  but  placed  on  the  lower  string  of 
the  Newark  Dyke  Bridge.  The  next  example,  (No.  15)  is  the 
Saltash  Bridge,  which  w^s  erected  by 
Brunei!.  It  is  known  by  the  name  of 
"Fish"  girder,  on  account  of  the  construction 
of  the  truss  which  is  formed  by  reversed  seg- 
ments of  circles  of  cast  and  wrought  iron 
plating  connected  by  vertical  and  diagonal 
bracing  to  which  the  roadway  is  suspended. 
It  is,  however,  less  economical  than  the  forms 
of  girders  founded  on  the  Warren  type,  and  so 
lias  had  no  children.  The  next  illustration 
(No.  16)  shows  an  example  of  a  wrought  iron 
arch  bridge  over  the  Ehine  at  Coblentz. 
But  it  is  of  no  greater  span,  nor  so  econom- 
ical in  construction  as  many  of  the  preceedino- 

£  £    1      -J  11  8 

rorms  or  bridges,  and  hence  cannot  compete 
with  then  in  universal  adoption.  The  next  ex- 
ample (No.  17)  shows  the  Fink  type  of  truss. 
In  this  girder  each  division  comprises  a 
separate  and  distinct  truss,  all  combined  in 
one  by  the  boom  or  horizontal  tie  which 
supports  the  roadway  of  the  structure.  It 
is  composed  wholly  of  vertical  cast  iron  struts, 
inclined  wrought  iron  braces,  and  one  hori- 
zontal tie.  It  is  a  worthy  competitor  of  the 
Warren  girder  as  regards  economy,  but  is  less 
pleasing  in  form. 


The  Niagara  Suspension  Bridge,  (No.  18)  is  the  next  example. 
It  crosses  the  Niagara  River  some  distance  below  the  falls  at  a 
height  of  245  feet  above  the  water  by  a  single  span  of  821  feet, 
6  inches.  The  main  structure  is 
a  hollow  rectangular  box.  The 
steam  cars  traverse  the  upper 
surface,  while  the  carriages  pass 
through  the  tube.  The  walls 
are  formed  of  double  vertical 


ent  versed  sines  has  been    criticised  as    a  defect  in  the    principle 
of  this  bridge. 

Tn  this  mode  of  construction  the  tube  and  the  truss  have 
been  combined  with  the  suspension  principle,  as  introduced 
above,  showing  the  progressive  development  of  the  idea  of  adap- 
tation of  means  to  ends,  which  is  so  marked  a  characteristic 
of  the  present  age,  and  the  drawing  attention  to  which  is  one  of 
the  chief  objects  of  this  paper,  especially  in  connection  with  the 


l/V^fN/WWJVWWWV 


timbers  with   wrought  iron  din.g- 

o  o 

onal  bars  crossing  between  them. 

The    railway    or   upper   floor    is 

carried  by  two  wire  cables,  while 

the  carriage  way  or  lower  floor  is 

carried    by   two    others,  four  in 

all.       The  total   sectioal  area  of 

iron  is  24  1 1  square  inches.    This       NEWARK  DYKK  BRIDGE. 

bridge  was  commenced  in   1852.  8*0.13) 

and  open  for   traffic   in    1855.     It    was    designed    and   built    by 

Roobling,  and  cost  .£80,000.     The  use  of  the  two  cables  of  ditt'er- 


NIAGARA  SUSPENSION  BRIDGE.     (Xo.  18) 

bolted  together  and  braced  laterally  and  connected  by 
wrought  iron  couplings,  which  were  found  better  for 
the  purpose  than  steel.  The  tubular  ribs  are  in  sec- 
tions 12  to  13  feet  long,  and  from  1J  to  2J  inches 
in  thickness.  It  is  designed  to  carry  a  double  rail- 
way below,  and  foot  passengers  above. 

The  next  example  (No.  ?1)  shows  the  great  Garabit 
Viaduct,  lately  erected  by  Mr.  Eiffel.     It  is  a  combi- 
nation of  a  wrought  iron  lattice  arch  carrying  a  lattice 
trussed  girder.    It  is  of  great  height,  640  feet  span,  and 
a  very  masterly  work.      It  was  built  by  means  of  sus- 
pension cables,  very  much  on  the  same  principle,  but  by  different 
methods  to  that  adopted  in  the  Forth  bridge  shortly  to  be  noticed, 
viz.,  without  scaffolding. 


FINK  TRUSS.      (No.  17) 

development  of  the  same  principle  in  architecture.  The  next 
examples  of  Arch  and  Girder  construction,  the  first  in  America, 
and  the  other  in  France,  show  characteristic  methods  of  spanning 
great  spaces  by  permanent  structures  on  sound  principles. 

The  St.  Louis  and  Illinois  Bridge,  (No.  19)  over  the  Mississippi, 
is  a  fine  example  of  metal  arcli  construction.  It  is  in 
three  spans,  the  center  520  feet,  side  spans502  feet 
wide  respectively,  and  presents  a  novelty  in  bridge 
building.  The  spans  of  the  arches  are  among  the  w.dest 
of  the  kind  in  the  world.  The  rise  of  the  center  arch 
is  47 1  feet.  Captain  Eads  was  the  engineer,  and  he 
must  be  credited  with  having  designed  and  erected  one 
of  the  finest  bridges  of  any  age.  Each  span  consists  of 


four  double 


inches  diameter, 


ARCH, BRIDGE  AT  COBLENTZ.    (No.  16) 

The  Brooklyn  Bridge,  (No.  21 )  of  which  I  here  produce  an  illus- 
tration, is  the  next  great  work  to  notice.  It  is  1,900  feet  be- 
tween supports,  with  piers  320  feet  high,  and  is  250  feet  above 


CRUMUN  VIADUCT.      (No.  14) 


the  East  River.  It  is  a  mighty  structure,  and  a  daring 
and  wonderful  achievement.  It  also  is  a  combination  of 
tubular  truss  to  secure  lateral  stiffness,  with  suspension  cables  as 


PART  OF   CRUMTJN  VIADUCT. 

est  of  the  many  magnificent  undertakings  brought  *o  a  successful 
accomplishment  in  recent  years. 

The  Firth  of  Forth  Cantilever  Bridge  (No.22  3)  is  another  struct- 


supporting  agents.     Cable  cars,  carriage  roads  and    foot   passen-       ure  of  immense  proportions,  and  of  great  complexity,  being  a  com- 
ger  ways  are  provided,  and  the  whole  constitutes  one  of  the  great-       bination  of  wrought  iron  arch-tubes,  vertical  and  inclined  tubular 


"=2?A-<-2' 

ST.  LOUIS  AND  ILLINOIS  BRIDGE.    (No.  19) 


columns  or  posts,  pitching  inwa-ds,  double  suspension  bearings 
latticed  together,  and  gr^at  latticed  catenaries  supporting  a  con- 
tinuous box  girder-tube  which  passes  through  the  whole,  carrying 
the  railway  track.  The  span  is  1,710  feet,  besides  the  side  ap- 
proaches. It  is  constructed  on  the  stab/eequlibrium  principle,  and 
is  wholly  built  of  steel  without  scaffolding.  It  is  without  question 
the  most  stupendous  structure  of  the  kind  in  the  world,  and  will 


scarcely  be  blown  down  like  the  Tay  Bridge,  in  1886.  The 
above  structure  is  a  combination  of  arch  and  catenary,  with 
the  lattice  principle.  It  is  constructed  by  building  out  piece 
by  piece  from  each  side  of  the  central  supporting  piers.  It  in  fact 
provides  its  own  scaffolding,  and  grows  by  gradual  accretion  of 
balanced  parts  as  a  tree  does,  and  on  the  same  principle,  thus 
indicating  a  closer  and  closer  return  to  nature  by  man  as  he 


2 


assiduously  studies  her  economic 
processes.  Nevertheless,  the  ap- 
parent striking  disporportion  be- 
tween means  employed  and  ends 
subserved  is  so  manifest  in  this 
structure  as  to  suggest  grave 
doubts  as  to  the  soundness  of 
some  of  the  principles  of  design 
employed  therein. 

The  next  illustration  here 
shown  (Nos.  23,  24,  25  and  26) 
is  the  proposed  great  North 
River  Bridge  at  New  York. 
This  enormous  but  beautiful 
struct  ire  as  it  is  designed,  will  be 
fully  twice  as  large  as  the  great 
Brooklyn  Bridge.  It  is  to  be 
2,820  feet  span  between  sup- 
ports. The  towers  will  be  of 
stael,  and  620  feet  in  height. 
It  will  cost  $40,000,000,  whih 
the  cost  of  the  former  was  only 
15,000,000. 

The  bridge  itself  is  formed  of 
latticed  girders  carried  on  lat- 
ticed cables.  The  whole  prom- 
ises to  be  the  grandest  single 
span  structure  that  has  yet  been 
conceived. 

It  will  be  seen  that  in  each 
of  the  above  structures,  while 

the  technical,  the  utilitarian,  the  objective  qualifications  have 
in  every  case  almost  wholly  governed  the  design,  the  result 
has  also  partaken  of  the  higher  esthetic,  ornamental  and  artis- 
tic qualities  in  a  remarkable  degree.  From  the  straight  sim- 
ple bar-like  effect  of  the  Britannia  Bridge,  imposing  from  its 
magnitude  and  simplicity,  to  the  great,  sweeping  curve  of  the 
catenaries  of  the  proposed  North  River  bridge,  each  design 
has  presented  features  and  combinations  of  features  clearly  ex- 
pressed and  resulting  in  a  peculiar  beauty  which  no  mere 
architectural  accessory  could  in  any  way  produce.  Not  one  of 
these  designs  depends  for  its  effectiveness  on  any  purely  archi- 
tectural detail  as  usually  understood,  but  it  is  due  entirely  to  the 
proper  distribution  of  parts  in  the  most  efficient  way  that  could, 
at  the  time,  be  reasoned  out  for  the  proper  attainment  of  the  ob- 
ject in  hand.  This  we  have  to  insist  on  again  and  again.  It 
is  the  iron  rule  which  can  never  be  broken  without  departing  from 
true  principle,  and  with  unhappy  results  to  the  beauty  of  the 
structure  concerned,  from  the  designing  of  the  simplest  moulding 
to  the  construction  of  a  cathedral,  the  erection  of  abridge,  or 
the  building  of  a  ship.  It  it  the  one  paramount  law  in  Art  and 
Science,  as  imperative  in  such  an  apparently  variable  and  volatile 
thing  as  a  lady's  bonnet,  as  in  the  construction  of  that  useful, 
beautiful  and  significant  thing,  the  steam  engine. 

To  evince  the  truth  of  this  proposition  we  will  present  one 
more  well  known,  nay,thsperaps,  in  past  times,  somewhat  hack- 
neyed example,  to  close  this  series  of  illustrations  of  the  very  im- 
perfect remarks  to  which  you  have  so  kindly  and  forebearingly 
listened.  I  allude  to  the  one  great,  significant,  and  really  original 
building  of  the  century.  The  conception  of  no  professional  archi- 


THR  GREAT  GARA BIT  VIADUCT.    (No. 

tect,   for  no  architect   out  of    245   who  competed  for  it.   prmrd 
equal  to  the  task. — No    builder;   for   none    were    found    in    the 
length  and  breadth  of  England  who  could  suggest  such   a  struc- 
ture; but  of  a  mere  gardener,  a  constructor  of  green  houses. — I 
allude    of    course,   to  the  Great  Exhibition    Building  of     1S51. 
Truly  great  it  wns,  and  greatest,  even,  it  will   remain,  until    once 
again  the  exigencies  of  the  occasion    shall    override    mere  prece- 
dent, and  some  future  gardener  shall  produce  as  glorious  a  flower 
from  as  small  a  seed,  simply  by  yielding  unquestioning  obedience 
to  the  needs  of    the  occasion,  unfettered  by  rule    or  any  existing 
order    of  things  which    could  in  any  wav   interfere    with  or  en- 
cumber pure  utility.    The  design  sprang  into  being,  and  the  world 
of  that  day  was  both  astonished  and  delighted.     It  is  said    that 
when  all  the  designs  for  the  Great  Exhibition    of    '51    had  been 
received,  classified  and  inspected,  and  the  commissioners,  rejecting 
them  all,  had  concocted  one    of    their  own,  apparently  as  unsuit- 
able for  the    purpose,  as  any    one    of  them    all,  Joseph    Paxton, 
chief    gardener    to    the     Duke    of     Devonshire,    sat    down    in 
his   office    and    in    half    an     hour    sketched    out   his    design  for 
the      proposed      building     on     a     sheet    of     foolscap.          Sub- 
mitting   his    idea    to    one    of    the    Commissioners,    he    \vas  en- 
couraged   to    perfect    it.     The    design    was    published    and    re 
ceived  the  unanimous  approval  of  the    nation.     The  contractors, 
Fox  cfc  Henderson,  in  one  week  prepared  drawings  and  estimates, 
and    in    four  months  from  that  date,  18  acres  were  covered  with 
glass  and  iron  in  a  structure,  the  quiet  be  auty,  majestic  simplicity 
and  the  unapproached  convenience  of  wihch  has  been  from  that  day 
to  this,   absolutely  unrivalled    in  buildings  of  the    kind.     Every 
building  of  the  sort  since  designed,  has  had  a  variety  of  accessor- 
ies breaking   up  its  mass    by- 
useless  excrescences  until  the 
fantastic  structures  have  final- 
ly   lost    every     characteristic 
which  made    tho   original   de- 
sign  great.       The    uccom pan- 
ing  views,  show  exterior  and 
interior  views,  and  a  few  de- 
tails.  (Nos.  27,  2f ,  29  and  :!0) 
The  account  of  the  design- 
ing, and    construction  of  this 
building,    reads    like    a    fairy- 
tale,    in    harmony    with     the 
fairy  like  structure  which  was 
the  charming  result. 

Mr.  Henderson,  who  made 
every  important  drawining 
with  his  own  hand,  working 
18  hours  a  day  for  seven 


TIRTH  OF  FORTH  CANTILEVER  BRIDGE.     (No.  22) 


FIRTH  OF  FORTH  CANTILEVER  BRIDGE.     (No.  23) 


weeks,  says  in  a  speech  made  about  that  time,  tiiat  hundreds  of 
tons  of  glass  were  provided,  of  an  unprecedented  size; 
thousands  of  columns,  hundreds  of  girders  34  miles  of 
guttering  pipes  connecting  the  columns,  which  conveyed  the 
rain  water  to  the  ground,  205  miles  of  sash  bars,  and  more 
than  1, OQO,000  feet  of  flooring,  were  produced  by  the  various 
firms  engaged  in  the  work,  in  the  short  space  of  time  which 
was  allowed  to  execute  it.  The  setting  out  of  the  structure, 
the  placing  of  the  base  blocks  on  concrete  filled  into 
holes  dug  in  the  ground,  the  raising  of  the  columns,  the 
lifting  of  the  girders  and  keying  them  into  their  proper  places 
in  the  structure,  etc  ,  proceeded  with  unexampled  accuracy  and 
rapidity,  and,  the  first  of  its  kind,  and  unique  in  the  history  of 


great  expositions,  the  building  was  ready  on  the  day  when  the 
contract  expired.  This  was  clue  to  the  entire  simplicity  and  re- 
duplication of  every  part  of  the  structure,  which  again  was  due  to 
the  harmony  of  scale,  which  in  this  structure,  as  in  the  Parthenon 
and  a  few  others,  is  perhaps  after  all,  the  most  noticeable  feature 
in  the  building. 

Contemplating  the  excellent  qualities  exhibited  by  this 
great  structure,  which  at  the  time  of  its  erection,  challenged 
the  admiration  of  men  of  taste  and  judgment  throughout 
the  world,  and  in  fact,  elevated  it  to  a  level  with  the  greatest 
edifices  ever  conceived  by  man,  it  is  evident  that  it  in 
no  way  differs  in  kind  from  any  one  of  the  great  engineer- 
ing works  to  which  your  attention  has  been  directed  above. 


NORTH  RIVER  BRIDGE.      (No.  34) 


Adaptation  of  means  to  ends  and  that  alone,  in  it,  as  in  them, 
constitutes  and  includes  all  of  its  qualifications,  and  in  this  as 
in  them,  it  is  especially  to  be  remarked  that  there  is  nothing 
imitated.  No  attempt  is  made  to  transfer  to  one  material  the 
appearance  or  proportions  appropriate  to  another.  On  the  con- 
trary, each  material  is  in  its  turn  treated  on  its  own  merits,  and 
hence  its  value  is  thereby  enhanced  in  proportion.  It  is  just  as 
though  the  whole  structure  to  its  minutest  part,  was  represented 
by  two  sets  of  figures,  indicating  in  the  first  place  the  intrinsic 
value,  in  the  other  the  value  in  application,  and  that  both  sets  of 


figures  in  every  case,  were  identical.  In  how  many  structures 
of  the  kind,  erected  before  or  since,  can  this  be  said  to  have  been 
attained.  In  other  words  that  every  material  throughout  the 
structure  should  be  so  applied  as  to  attain  the  greatest  measure 
of  utility  it  is  capable  of,  with  the  least  expenditure  of  material 
compatible  with  safety,  and  with  the  best  artistic  effect.  Would 
it  be  by  adopting  the  forms  and  construction  appropriate  to  some 
other  and  very  different  materials?  to  make  iron  resemble  stone 
for  instance,  or  wood  iron  or  vice  versa?  It  is  evident  that  there 
must  be  in  such  a  case  a  great  and  useless  waste  of  labor  as 


well  as  material,  in  other  words,  that  the  intrinsic 
and  economical  values  would  fail  to  agree.  Note 
the  admirable  way  in  which  every  part  of  the 
above  great  building  is  adapted  to  every  other 
part!  The  way  in  which  the  columns  rise  from 
ground  to  roof  line,  representing  every  one  of  the 
direct  lines  of  support  throughout.  The  way  in 
which  the  connecting  girders  and  filling  in  pieces 
are  keyed  rather  than  bolted  into  their  places, 
and  how  directly  and  easily  every  part  does  its 
duty,  and  how  by  the  proportioning  of  material 
to  strength  and  position,  such  a  degree  of  aerial 
elegance  is  attained  that  it  may,  perhaps,  best  be 
compared  to  the  delicate  twigs  and  branches  of  a 
tree  divested  of  its  leaves,  whose  dainty  pencil- 
ings  tax  the  skill  of  the  artist  fitly  to  represent. 
When  in  the  full  glory  of  its  utility,  it  overflowed 
with  a  profusion  of  fabrics  and  materials,  and 
objects  of  beauty  and  use  from  every  quarter  of 
the  globe,  it  was  like  the  same  tree  in  full  bloom,  glowing  with 
verdure  .  with  color  and  with  fruit. 

It  seems  at  this  point    permissible  to  consider,  as  a  compara- 
tive   test  of  the    proper   treatment    of  other    materials,   some  of 
the    reeognized    qualities  and    properties  of  Iron.     Whether  as 
wrought  or  cast  iron,  or  in  the  form  of  that  now  abundant  material, 
wrought  and  cast  steel,  innumerable  tests    and  experiments  have 
settled  to  so  large  an  extent  the  available  qualities   of    all    these 
substances    that   there    is    no   particular   need  of    dilating    upon 
that  subject  further  than  may  suffice  to  note  some  of  the  ways  in 
which  they  may  be  better  used  and  less  abused.      In  the  first  place 
it  must  not  be  forgotten  that  all  materials,  without  exception,  are 
subject    to    change,    that   no   material,    whatever    its   form    or 
qualities,    is  free  from  the  liability    to  alter  its  shape;  and 
that  therefore  when  a  perfectly  spherical  cast  iron  ball  rests 
upon  its  side,  it  is  no  longer  spherical,  it  is  really  oblate. 
That  a  piece  of  cast  iron  ten  inches  square  in  section  and  a 
standard  foot  in   length,  if  placed  resting  on  its  extremities,      ~— 
is  no   longer  a  standard  foot  in   length,  and   that   when  a 
great  weight  is  placed  unsym metrically  on  any   form  of  sup- 
port, that  support  will  be  acted  on  unsymmetrically  and  will 
change  its  form,  and  the  arrangement  of  all  its  molecules 
in  the   effort  to  adjust  itself  to  the  conditions  thereby  imposed 
upon  it,  which  in  construction  means  a  great  deal,  involving  as  it 
does  under  given  conditions  the  theory  of  re-crystallization,  etc. 

We  are  accustomed  to  suppose  that  our  friends,  the  engineers, 
are  the  men  above  all  others  who  are  used  to  taking  account  of 
the  minute  changes  in  the  form  and  direction  of  the  substances 
and  forces  with  which  they  have  to  deal. 

But  architects  are  expected  to  abolish  all  such  changes, 
and  to  produce  a  structure  of  variable  materials  abso- 


APPROACHES  TO  THE  NORTH  RIVER   BRIDGE.       (No.  25) 

lutely  fixed  in  form  for  ever;  at  least  so  one  would  suppose 
from  the  "sort  of  criticism  to  which  they  are  at  times  subjected. 
But  it  is  to  be  feared  that  they  themselves  are  chiefly 
responsible  for  the  inappropriate  use  too  often  made 
of  materials,  and  the  untoward  results  which  frequently 
occur.  Uniformity  of  material  means  uniformity  of  action 
in  the  changes  which  those  materials  inevitably  undeigo 
underthe  influence  of  temperature  and  strain.  Some  of  the  \vnvs 
in  which  iron  should  not  be  used,  we  beg  now  to  note, 

First:  No  great  strain  ought  at  any  time  to  be  thrown  in  nn 
unsymmetrical  manner  on  any  unsymrnetrical  section  of  cross  iron. 
This  means  an  unequivocal  condemnation  of  brarke/s.  The  extent 
to  which  that  mode  of  employing  cast  iron  is  used,  is  remarkable 


CAST  IRON  BRIDGE  AT  CRAIGELLACHIE. 

when  the  treacherous   nature  of   the   material  so  used  is  so  well 
known. 

To  founders  and  machinists  who  are  well  and  practically  ac- 
quainted with  the  behavior  of  cast  iron  under  strain  and  tem- 
perature, there  is  nothing  more  objectionable  than  a  large  extent 
of  cross  iron,  as  it  is  called.  They  refuse  to  trust  to  it  under  any 
circumstances  and  yet  we  find  in  all  the  published  examples  an 
almost  unlimited  use  of  this  objectionable  and  dangerous  feature., 
Smooth,  round  columns  of  cast  iron  of  small  diameter,^ 
are  set  upon  end  and  a  number  of  brackets  are  projected 
from  them  at  a  sharp  angle  at  cap  and  base  plate,  bearing 
heavy  loads  of  beams  and  arches  and  this  for  many  stories  in 
height.  Such  an  accident  as  occurred  in  the  Owens  Building, 
at  Chicago,  or  an  unsuspected  flaw  in  one  of  the  brackets  or  any 
other  adequate  reason,  causing  the  snapping  of  one  small  section, 
may  possibly  occasion  in  a  moment  the  destruction  of  a  large 
building,  hundreds  of  lives  and  much  valuable  property.  Is  this 
either  wise  or  necessary?  Can  bad  construction  ever  be  neces- 
sary? Is  it  scientific?  Isitartistic?  That  there  are  few  authen- 


TOP  OP  TOWER,  NORTH   RIVER    BRIDGE. 
(No.  26) 


SPAN  OF  SALTASH  BRIDGE.     (No.  15) 

tic  cases  of  failure  of  this  kind  that  can  be  referred  to  is  no 
argument  in  favor  of  the  practice.  Is  it  not  something  which 
may  occur  under  any  sudden  shock?  The  fall  of  compara- 
tively few  degrees  of  temperature,  in  view  of  the  great  inequality 
between  bracket  and  shaft,  must  cause  unequal  strains  in  both. 
A  settlement  causing  undue  strain  on  any  one  part,  or  a  local 
rise  of  temperature,  or  some  stress  occasioned  by  any  one 
of  a  hundred  different  causes,  may  ultimate  the  con- 
ditions which  may  bring  about  a  failure  such  as  I  have 


BROOKLYN   BRIDGE,    NEW   YORK.      (No.  21) 


indicated.  Another  wrong  use  of  the  material  is  indicated 
in  the  ordinary  form  of  cast  iron  girder  in  which  the  upper  flange 
is  arched.  This  is  an  altogether  mistaken  idea,  and  an  utterly 
falUcious,  improper,  and  unscientific  use  of  material.  In  the  gir- 
der here  shown  (No.  31)  the  lower  flange  is  straight;  the  shortest 
distance  between  the  two  ends,  in  the  upper  flange,  the  di»tance  is 
the  greatest  that  can  be  found  between  the  two  ends.  In  cooling 
flange  (A)  occupying  greater  length,  shrinks  more  and  flango 
(l>)  being  shorter,  shrinks  less,  in  proportion;  consequently  there 
is  an  internal  strain  set  up  between  the  top  and  bottom  flanges 
and  brought  to  bear  upon  the  web,  which  added  to  the  weight 
that  the  girder  is  supposed  to  bear,  greatly  lessens  its  effective 
strength,  if,  (as  in  large  girders  of  this  form,  is  a  frequent  result,)  it 
does  not  occasion  their  destruction.  This  is  one  of  the  principal 
reasons  why  such  cast  iron  girders  frequently  snap,  even  befor^  be- 


ing placed  in  the  building.  The  ordinary  form  of  the  rolled  girder, 
indicates  also  the  best  general  form  for  a  cast  iron  girder  under 
ordinary  circumstances.  Parallel  flanges,  the  upper  one-half 
the  width  and  thickness  of  the  lower,  with  square  or  in- 
clined skewbacks  at  the  end,  indicate  generally  the  best  practical 
form  for  cast  iron  girders  of  short  span.  (No.  32) 

Tin;  latticed  girders  used  in  the  great  exhibition  building  (No.  29) 
were  in  every  respect  admirably  adapted  to  the  purpose  for  which 
they  wore  intended;  and  either  as  stiffeners  for  the  nave  columns, 
in  which  position,  of  course,  they  were  much  lighter,  or  as  the 
bearers  of  the  gallery  floors,they  were  found  in  every  respect  equal 
to  their  work. 

Before  closing  these  perhaps  too  lengthy  remarks,  I  will  venture 
to  indicate  a  few  ways  in  which  it  may  lie  found  advantagfous 
to  use  cast  iron.  Describe  a  circle  in  a  square,  ^No.  33)  and  lill 


LONDON   EXHIBITION   BUILDING   OF   1851.    (No.  27) 


in  the  angles  of  the  square  with  other  squares;  apply  the  thick- 
ness of  one  of  the  small  squares  round  the  circle  internally,  and 
you  have  the  section  of  a  cast  iron  column  of  any  diameter,  and 
any  length  within  the  prescribed  limits  of  30  diameters.  In  ele- 
vation, place  the  flanges  diagonally  (as  they  are  drawn)  to  the 
length  of  the  superimposed  girders.  Grow  the  flanges  out  bv 
means  of  curves,  into  brackets  of  modraete  projection  and  cast  a 
plate  of  equal  thickness  on  top,  andthe  cap  is  formed.  A  greater 
projection  and  a  proportionately  larger  plate  forms  the  base.  If 
supporting  a  great  weight,  as  in  the  case  of  a  basement  column, 
separate  the  base,  and  form  circular  flanges  between  the  angle 
ribs,  on  shaft  and  base  sections,  and  bolt  the  two  together.  To 
adjust  wrought  I  beams  to  this  form  of  columns  continued  two 
or  more  stories  in  height;  cut  away  the  flanges  of  beams  next  the 
columns  on  each  side  (using  coupled  beams)  and  fit  the  same  to 
flanges  of  columns,  and  bolt  diaphram  platos  between  the  beams, 
(which  should  always  break  joint)  on  each  sideof  column.  In  this 
way  a  perfectly  immovable  system  of  columns  and  girders  is  formed, 
symmetrical  in  bearing,  and  adjusted  to  the  required  conditions 
throughout.  The  brackets  are  simply  extensions  of  the  ribs, 
and  there  is  710  initial  point  of  fracture,  and  the  gird- 
ers, on  account  of  being  firmly  held  at  each  end,  will  bear 
double  the  weight  of  unfixed  girders.  If  it  is  desired  to  fire- 
proof these  columns  and  girders,  the  shafts  and  brackets  are 
admirably  adapted  thereto.  One  other  suggestion  and  I  will  con- 
clude this  section.  The  subject  of  Tempering  is  one  which 
does  not  seem  to  have  attracted  the  attention  of  construc- 
tionists  to  any  large  extent  up  to  the  present  time.  A 
gentleman  of  my  acquaintance  in  Ontario,  Canada,  some  years 
ago,  patented  a  carriage  spring  of  peculiar  merit.  Instead  of  be- 
ing made  in  the  usual  way  of  several  laminae  of  thin  steel,  secured 


with  rivets  or  loops,  it  was  made  solid,  ogival  in  form,  and  tem- 
pered in  an  oven.  The  reason  why  springs  had  never 
been  made  solid  before  was  because  it  was  not  easy  to  give 
equal  temper  throughout  the  thick  and  thin  parts.  This  was 
secured  by  means  of  an  oven  of  a  peculiar  kind.  The  ogival 
form  of  the  spring  causes  the  bearing  to  be  shortened  with  the 
increase  of  load.  Why  is  not  this  a  principle  which  might  be 
taken  advantage  of  in  designing  cast  or  wrought  steel  lattice 
girders,  (No.  34)  and  why  should  they  not  be  tempered?  The 
tempering  alone,  the  gentleman  informed  me,  added  300  per  cent, 
to  the  strength  of  the  springs. 

The  lately  invented  method  of  rendering  iron  unoxidizable, 
known  as  the  "Bower-Barf"  process,  by  which  a  film  of  carbon- 
ate of  iron  is  formed  on  the  surface  of  the  metal,  seems  calculated 
still  further  to  increase  the  availability  of  iron  as  a  building 
material. 

In  conclusion,  it  is  in  order  to  revert  briefly  to  the  original 
title  of  this  paper,  "  The  Iron  Age." 

While  to  speak  in  parables  in  the  promulgation  of  truth  and  to 
embody  symbolism  in  the  statement  of  principles  has  been,  per- 
haps, peculiarly  characteristic  of  past  times,  and  of  people  of  a 
genius  different  to  ourselves,  to  clearly  formulate  the  same  princi- 
ples, in  logical  terms  and  in  unmistakable  language,  is  believed 
to  be  the  special  province  of  the  philosophy  of  the  present  day. 
And,  while  this  may  be  conceded  so  far  as  it  goes,  it  is  also  certain 
that  the  wisdom  of  our  own  times  still  continues  to  be  embodied 
in,  as  that  of  other  times  must  be  interpreted  by,  modes  of  utter- 
ance which  condense  into  single  expressions  the  ideas,  sentiments 
and  general  characteristics  qualifying  whole  ages.  Just  such  a 
term  is  the  one  above  mentioned,  as  expressing  the  peculiarities 
of  our  own  time  or  age.  One,  indeed,  it  is,  in  which  the  fallacies 


10 


INTERIOR  VIEW   GREAT   LONDON   EXHIBITION   BUILDING.     (No.  28) 


of  the  past  are  being  tried  in  the  furnace  of  modern  scientific 
research,  and  tiie  pure  metal  of  simple  utility  is  being  evolved 
from  the  comparatively  worthless  philosophistical  Haematite  and 
Iron  Stone  of  former  eras.  And  lo!  everywhere  and  in  every 
sphere  of  human  endeavor,  order  is  emerging  from  confusion,  and 
progressive  development  takes  the  place  of  stagnation;  and  in 
religion,  politics,  science  and  art,  the  symmetrical  lines  of  the 
Social  Structure  begin  to  appear  and  to  assume  an  aspect  in  some 
degree  corresponding  with  the  material  improvements  in  so  many 


Diagonal  Bracing  used  in 
above  building   t(No  .29) 

directions  visible  round  about  us.  In  the  pregnant  words  of  the 
Son  of  Amoz,  luminous  as  they  are  with  the  true  spirit  of  pro- 
phetic utterance,  "  For  Stones  I  will  bring  Iron  '."  But  not  only 
must  the  useless  representative  of  a  false  philosophy  be  ex- 
changed for  the  rational  science  of  an  advanced  civilization,  but 
the  rotten  symbol  of  a  spurious  morality  must  give  place  to  a 
more  enduring  substance  in  the  Social  Fabric  of  the  day;  for  the 
grand  old  prophet,  with  a  rocket-like  forecast  of  3,000  years, 
goes  on  to  say,  "For  H'ood  (I  will  bring)  Brass  !"  But  neither 
iron  nor  brass — nor  the  principles  they  represent — will  suffice  the 
great  artificer  who  builds  above  the  heavens!  for  the  one  will 
rust  and  the  other  will  tarnish,  and  the  structures  they  build  will 
go  to  decay,  containing  as  they  do  the  elements  of  their  own 
destruction  within  themselves;  for,  though  iron  may  be  converted 
from  the  coarsest  "pig"  to  a  substance  lustrous  as  silver  and 
strong  as  adamant,  it  represents  only  a  selfish  rationalism  at  best; 


DIAGRAMS  SHOWING  31,  V,  33  and  34. 


11 


and,  though  brass  may  endure  for  a  while  and  superficially  burn 
with  a  glory  like  gold,  it  exemplifies  only  the  poisonous  egoisms 
of  the  age,  and  both  ic  and  its  antitype  will  blacken  in  time.  It 
is  only  another  word  for  the  conventional  policy  of  the  day.  So 
again  the  prophetic  voice  comes  proclaiming  across  the  centuries 
in  a  still  loftier  strain:  "For  Iron  I  will  bring  Silver!''  Not 
Rationalism  and  its  fallacies,  however  scientific  and  intellectual, 
nor  mere  morality  with  its  sophistries,  persuasive  though  they  be, 
can  redeem  the  age  or  restore  the  lost  lineaments  of  divine  human- 
ity to  the  race;  but  an  enlightened  spiritual  philosophy,  which  is 
also  rational,  must  prevail,  whereby  the  high  principle  which  re- 
gards the  true  well-being  of  mankind,  in  the  broad  sense  of  univer- 
sal brotherhood,  may  be  realized  in  the  new  social  science 
which  must  more  and  more  mould  the  social  organism  of  the 
world.  But  not  even  silver  alone,or  the  high  principle  it  repsesents, 


will  suffice  for  the  structure  of  the  City  of  the  Soul,  for  once  again 
the  final  promise  comes  as  truly  as  of  old,  in  divine  prophetic  utter- 
ance.saying,  "For  Brass(I  will  bring)  Gold."  For  the  sympathies 
and  perceptions  as  well  as  the  sensibilities  and  sentiments  of 
men  must  be  aroused,  and  mediate  good  or  the  love  of  man, 
represented  by  silver,  must  be  vitalized  tiy  essential  good  or  the 
"love  of  God,"  represented  by  "Gold''  "like  unto  transparent  glass." 
And  t/iese  must  be  the  substances  out  of  which  the  mental, 
moral,  yea  the  spiritual  •'habitations"  of  mankind  must  be  con- 
structed, ere  the  true  Golden  Age  of  perfected  wisdom  can  come 
again  in  place  of  tin-  original  Golden  Age  of  untried  innocence  in 
the  prehistoric  childhood  of  the  race!  Then,  and  then  only  can  the 
Spiritual  Jerusalem  be  said  to  be  indeed  established  among  men, 
in  the  good  time  coining,  in  the  far  offn'ons  of  futurity. 


14  DAY  USE 

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